M000003539

$$\pi=8\arctan\left(\frac{1}{5}\right)+12\arctan\left(\frac{1}{15}\right)+8\arctan\left(\frac{1}{21}\right)+4\arctan\left(\frac{1}{34}\right)+4\arctan\left(\frac{1}{55}\right)+4\arctan\left(\frac{1}{57}\right)+12\arctan\left(\frac{1}{81}\right)-12\arctan\left(\frac{1}{467}\right)$$